Project Summary The SARS-CoV-2 (COVID-19) epidemic has been rapidly changing. Vulnerable populations, such as people who use drugs (PWUD), are particularly susceptible both to severe COVID-19 illness as well as health and well-being consequences associated with the secondary impacts of the COVID-19 epidemic. PWUD are at higher risk of COVID-19 due to high levels of comorbid health conditions and high incidence of respiratory impairment due to cigarette smoking. The health of PWUD are also influenced by social policies and practices implemented as part of COVID-19 response strategies. For example, COVID-19 social distancing measures and hospital access restrictions may reduce PWUD's ability to obtain HIV, HCV, and other types of critical health and social services. Those who are on medication assisted treatment may be at risk for treatment disruptions, and those who attend self-help groups such as NA and AA may be unable to attend meeting or see their sponsors. Engagement in COVID-19 prevention measures may also be more difficult for PWUD. High rates of homelessness and unstable housing among PWUD, may prohibit their ability to stay in place. As they may have no place to stay. Unstable sources of income and effort to avoid withdrawal symptoms may lead PWUD to more frequent interactions with others and less social distancing, as well as more frequent sharing of injection equipment. As COVID-19 is a novel disease and massive social changes have been implemented, which have not been utilized since the influenza epidemic of 1918, there is scant literature to aid us in predicting the long and short-term impacts of COVID-19 among PWUD. Consequently, we propose to conduct a mixed methods study that would entail frequent (bi-weekly) qualitative assessments of a sample of PWUD and a quantitative survey. We propose these frequent qualitative interviews as the situation may change rapidly depending on the epidemic dynamics. The parent grant (R01DA040488) is an RCT to improve HIV and HCV health outcomes and reduce HIV, HCV, and drug overdose risk behaviors among people who inject drugs (index participants) and their social network members.